Electronic Band Structure of Group IV 2D Materials: Graphene, Silicene, Germanene, Stanene using Tight Binding Approach

2D nanomaterials such as graphene, silicene, germanene and stanene are considered as one of the emerging research materials for transistor scaling. These materials have potential application in electronic, semiconductor and optoelectronic devices. In this present investigation, we have used the nearest neighbor tight-binding approach (NNTB) to explore the electronic band structure of these analogous 2D nanomaterials. It has been found that a 1.91 eV, 0.79eV, 0.S0eV and 0.60 eV bandgap can be successfully extracted from 4AGNR, 4ASiNR, 4AGeNR and 4ASnNR respectively. The extracted bandgap from 25AGNR, 25SiNR, 25GeNR and 25SnNR is calculated as 0.35 eV, 0.15eV, 0.15eV and 0.11 eV respectively. We have confirmed that for useful application of these nanomaterials in the semiconductor device, we have to keep the dimension of the nanodevices as small as possible. Besides, it has been found that at lower scale these nanomaterials exhibit direct bandgap which is useful for optoelectronic devices. We have demonstrated that as the width of nanoribbon increases that is device size, the possibility for extracting suitable bandgap for semiconductor devices reduces. Our computational approach suggests that as the ribbon width increases these nanomaterials behave like a conductor. Variation of extracted bandgap as a function of the device is also depicted. Our simulation results also suggest that extracted bandgap can be classified into three families of category. 3p and 3p+1 are suitable for semiconducting application whereas 3p+2 family is suitable for the semi-metallic application. These results may help to design and scale graphene, silicene, germanene and stanene based semiconductor devices.